If your brown colored "dust" wisps away in front of your vacuum, then it is probably not sand at all. The fact that it is brown probably suggests one of two possibilities.

First, you might just be having a problem removing an already dead algae. Dead algae can turn brown in the water. The fact that it is pushed away before your vacuum can catch and remove it suggests that your vacuum head has brushes on it. If so, it's possible that the brushes are actually pushing the algae away like a broom would. Instead, you might be more successful buying (or borrowing) a vacuum head that uses wheels on the underside rather than brushes. Go slowly over the bottom with the wheeled vacuum. If you have a sand filter, or can somehow direct your filter to vacuum to "waste" (sometimes labeled as "drain"), you could avoid the risk of reintroducing the "brown dust" back into the pool if it is small enough to pass through your filter. If you do vacuum to "waste" or "drain" you can vacuum a little more quickly as the suction in the vacuum will be greater and you don't want to remove too much water from the pool.

Second possibility: If you are successful with the suggestion above, but the brown dust returns soon afterward, then you may have another problem called "mustard algae". Mustard Algae can range from a mustard-like yellow to brown. If is very resistant to chlorine treatment, survives dehydration, and can be reintroduced by using the same vacuum hose, pole or head, if it has come into contact with mustard algae but not treated with a special mustard algae chemical killer.

Try to physically remove the dust first. If that fails, try to treat your water for mustard algae and remember to treat not only your pool water but all your equipment, etc., by soaking it with the same chemically treated water.

I have the same problem using either a cartridge or sand filter for a 16' intex pool. Only solution I found is to vacuum the pockets of brown matter. I use a shop vac that I modified to reach the bottom of the pool. It requires frequent emptying but does pickup the stuff. I also have a second cartridge filter pump that I rigged to do the same thing. In both cases you lose water but I haven't had any success with chemicals etc. I have wondered if a salt system would solve this issue.

I have the same problem with that brown stuff at the bottom of my pool. I have a salt water system and it is a booger to get rid of. I assume these cloudy looking brown spots are algea, I can vaccum them up, the water turns a little cloudy and several hours later the clouds are back at the bottom of the pool. I have a 15 x 48 above ground. How can I get get rid of these for good? My pump runs for at least 16 hrs a day in 4 hr intervals.

I'd first make sure you don't have dirt or pollen. If you can collect some and feel if it is slimy as opposed to squishy or gritty, then that would be helpful. You can also use a skimmer sock which would collect it if it were pollen (before it sinks).

Read Defeating Algae and shock your pool at a high yellow/mustard algae shock level which is a Free Chlorine (FC) level that is 60% of your Cyanuric Acid (CYA) level. Get behind light niches and removable ladders and put in pole and other equipment you use into the pool. Wash your swimsuits. Keep the chlorine high until the algae is gone and you measure minimal FC drop overnight (< 1 ppm is good, but at high shock levels < 2 ppm would be OK).

You may have gotten the algae because your FC is too low for your CYA level. In a saltwater chlorine generator (SWG) pool, you want the FC to be at least 4.5% of the CYA level so if your CYA is 80 ppm you want the FC to be at least 3.6 ppm minimum and 4 ppm would be safer. Yellow/mustard algae removal may require higher levels, but if you completely kill it off then this recommended minimum chlorine level should work. There are also copper-based algaecides, but these can stain though in your vinyl pool that may not be as much of a problem. There are also phosphate removers which will precipitate phosphate and prevent algae growth, but won't oxidize the algae already there (chlorine will do that).

If your CYA is very high, such as 80 ppm, then it may not be very practical to get to the mustard/yellow algae shock level. You could shock at the regular shock level that is around 40% of the CYA level (so 32 ppm FC), but this may not be sufficient unless you really get to every location in your pool where yellow/mustard algae likes to hang out (which is typically in shade). You should lower the pH to around 7.2 or somewhat lower before shocking with lots of chlorinating liquid or 6% unscented bleach (that you pour slowly over a return flow with the pump running and then lightly brush the side and bottom of the pool where you add it). Other alternatives include algaecides that work around a high CYA level and typically include either sodium bromide or ammonium, but these will create extra chlorine demand for some time. You can also use a phosphate remover which will precipitate phosphates and prevent algae from growing, but this won't oxidize the algae that is already there (chlorine will do that).

i just got rid of my mustard algae (what a pain). The brown stuff on the bottom is probably dead algae i kept vaccuming but as soon as i got close to it it would lift off the bottom. Vaccummed a couple of times a day (for about 3 days) to waste but could not get rid of all of it i always had like a brown thick film on bottom of pool and water would get cloudy from the stuff lifting up. Then i was told to use a floc. I was skeptical but i figured id give it a shot. i picked a bottle and thought it would not work. Filled my pool up to about 4 inches above skimmer scrubed with a brush the floor and sides of the wall to shake everything up put the flock in the pool ran the pump in circulate position for about .5-1hr. then i shut the pump off and left it undisturbed. when i looked at the water after 15 hrs. the water was crystal clear except for a white film on the bottom. I then set the pump to waste and vaccumed it all out. I had to vaccum out twice. The second time i had to add more water and let everyting settle to the bottom again. It tookme a whole week to get rid of it.

when i went to pool store i asked for floc. the bottle she gave me she said its the same as floc but they liked it better. Now when i looked at it the bottle says "alum" its made by pooltime . i'll try and upload a pic of it .

OK, thanks. Alum sometimes works and sometimes doesn't depending on what you've got in the pool. It's one of the early flocs used. I'm glad it worked out for you. OMNI Liquid Floc Plus is a proprietary cationic polymer blend -- probably more expensive, but more likely to work in more situations.

I was happy the way it worked. Actually the alum was $12.95 cdn and omni was $16.95cdn which was not much cheaper . I talked to some other people that had green and mustard algae and used the omni and they said it worked pretty good but nobody i know used the alum so i could not compare the difference . the only thing i know is that The Alum will give you a thicker layer of junk on the bottom of the pool than the omni.